1. Field of the Invention
This invention relates to killing of nematodes (round worms and more particularly to treatment of infections caused by parasitic nematodes.
2. Brief Description of the Prior Art
Strongyloides stercoralis is an intestinal parasitic nematode infecting more than 100 million persons worldwide. It is the most common parasitic nematode that is able to recycle and proliferate within its host. Chronic, usually asymptomatic, gastrointestinal infections result in the majority of otherwise healthy individuals, but in immunocompromised hosts or persons receiving immunosuppressive therapy inordinate multiplication of the parasite follows with dissemination of larvae and adults to virtually all organs of the body. This is a grave and often lethal condition.
Other parasitic nematodes, for example, of the genera Strongyloides, Ancyclostoma, Necator, Haemonchus, Ascaris, and Trichuris are also medically significant pathogens in humans and other mammals. Infections with Ascaris species afflict some 1200 million persons worldwide, and Trichuris infections afflict some 800 million persons.
Treatment of disseminated strongyloidiasis with ethically prescribed pharmaceuticals has met with problems of poor efficacy and harmful side effects. To date, the benzimidazole group of drugs has proved the most valuable. Thiabendazole has remained the drug of choice for the last 30 years, but twin disadvantages of unreliable efficacy and significant toxicity generally call for a search for a more reliable and safe compound. Some investigations point to the potential usefulness of a broad-spectrum anthelmintic, albendazole, for the treatment of strongyloidiasis, whilst others argue the efficacy of ivermectin, a macrocyclic lactone produced by the actinomycete Streptomyces avermitilis. 
The use of natural products in the treatment of intestinal helminths, which is venerated in Caribbean folklore, has received only limited attention. Reports and descriptions of such therapeutic uses may be found, for example, in Asprey & Thornton (1953) West Ind Med J 2:223-41; Davis & Persaud (1970) West Ind Med J 19:101-10; Lowe (1972) Jamaica Journal 8:20-4; Campbell (1974) Jamaica Journal 8:60-5; Honychurch (1980) Caribbean Wild Plants and Their Uses, Macmillan Press; Ayensu (1981) Medicinal Plants of the West Indies, Reference Pubs Inc.; Seaforth et al (1983) A Guide to the Medicinal Plants of Trinidad, Commonwealth Secretariat; McCallum (1985) UWI Med. Biography; Robinson et al (1990) West Ind. Med J 39: 213-7; Dias (1995) Newsletter—G-15 Gene Banks 718:4. About one hundred naturally occurring phytoproducts have been accredited with anthelmintic activity in vitro. On a wider scale, estimates indicate some 25,000 species of higher plants are used medicinally throughout the world where 80% of the population, most living in the tropic zones, rely heavily on traditional plant-based medications for health care. The potential of indigenous medicines is also recognised in the developed world, although to a much smaller extent. In the USA, for example, close to 100 secondary plant products have been incorporated as purified ingredients in more than 25% of prescribed preparations dispensed from the 1980's to the present time.
Accordingly, a need has continued to exist for the application of naturally occurring phytochemicals in the treatment of disease.